Cerium dioxide-based electrode-electrolyte pair (variants), method for the production thereof (variants) and organogel

ABSTRACT

This invention relates to the field of electric power generation by direct transformation of the chemical energy of gaseous fuel to electric power by means of high-temperature solid oxide fuel cells. The invention can be used for the fabrication of miniaturized thin filmed oxygen sensors, in electrochemical devices for oxygen extraction from air and in catalytic electrochemical devices for waste gas cleaning or hydrocarbon fuels conversion. The technical objective of the invention is the production of a low-cost electrode-electrolyte pair having an elevated electrochemical efficiency as the most important structural part of a highly efficient, economically advantageous and durable fuel cell. Furthermore, the invention achieves additional objectives. The achievement of these objectives is exemplified with two electrode-electrolyte pair designs and their fabrication methods, including with the use of a special organogel.

TECHNICAL FIELD

This invention relates to the field of electric power generation bydirect transformation of the chemical energy of gaseous fuel to electricpower by means of high-temperature solid oxide fuel cells.

Additionally, the invention can be used for the fabrication ofminiaturized thin filmed oxygen sensors, in electrochemical devices foroxygen extraction from air and in catalytic electrochemical devices forwaste gas cleaning or hydrocarbon fuels conversion.

STATE OF THE ART

Over the recent years, major attempt has been made world over aimed atthe development of high-temperature oxide fuel cells that act as uniquedevices for the generation of electric power from natural or syntheticgaseous fuels.

A high-temperature fuel cell consists of two porous electrodes having anelectronic conductivity type and a dense electrolyte in the spacebetween them having an ionic conductivity type. The gaseous fuel islocated at the side of one of the electrodes. The oxidizing agent,typically air, is located at the side of the other electrode.

The most important component of the oxide fuel cell structure thatdetermines the efficiency of electric current generation is theelectrode-electrolyte pair. The electrolyte of the fuel cell istypically doped cerium dioxide which has a good conductivity of oxygenions. Furthermore, the use of cerium dioxide electrolyte allows reducingthe fuel cell working temperature from 900-1000° C. to 600-700° C. Notethat the working temperature reduction objective is a top priority onefor the current research in this field.

The following electrode-electrolyte pairs are known.

Known is an electrode-electrolyte pair with a working temperature of950° C. wherein, aiming at reducing the cathodic overstressing and thechemical interaction between the main electrolyte consisting ofyttrium-stabilized cerium dioxide and a the cathode material consistingof lanthanum manganite, a gadolinium doped cerium dioxide separationlayer is introduced (U.S. Pat. No. 6,139,985 A, published 2000).

However, cerium dioxide in this electrode-electrolyte pair is notindependent electrolyte; rather, it has an auxiliary function.

Known is an electrode-electrolyte pair with a working temperature of700° C. wherein the porous anode surface is modified with a samariumdoped cerium dioxide film aiming at reducing the cathodic overstressing(S. P. Yoon, J. Han, S. W. Nam et.al. Performance of anode-supportedSOFC with Ni—YSZ or Ni-ceria anode modified by sol-gel coatingtechnique, 5^(th) European Solid Oxide Fuel Cell Forum, 2002,Lucerne/Switzerland, Proceedings, pp. 148-155).

However, the electrolyte in this electrode-electrolyte pair isstabilized zirconium dioxide instead of cerium dioxide, and this reducesthe efficiency of the fuel cell.

Known are electrode-electrolyte pairs with working temperatures of600-750° C. wherein the main element is yttrium, gadolinium or samariumdoped cerium dioxide (S. J. Visco, C. Jacobson, L. V. De Jonghe,Thin-film fuel Cells, Lawrence Berkeley National Laboratory).

However, the efficiency of this pair is insufficient. Moreover, thethermal expansion coefficient of cerium dioxide differs substantiallyfrom the thermal expansion coefficient of conventional electrodematerials. The resulting thermal stresses may destruct the electrolytelayer and/or electrode. The thinner the electrolyte layer, the greaterthe probability of cracking therein.

The following electrode-electrolyte pair fabrication methods are known.

Known is an electrode-electrolyte pair fabrication method comprisingdepositing a coating containing water solutions with a polymerizingorganic solvent (U.S. Pat. No. 5,494,700 A, published 1996) comprisingthe steps of:

producing a water solution of zirconium and yttrium nitrates, chloridesor carbonates;

mixing said water solution with ethylene glycol to act as a polymerizingagent;

adding nitric, hydrochloric, citric or oxalic acid for solution pHoptimization;

heating said mixture to 25-100° C. for polymerization and viscosityoptimization;

depositing said mixture onto the surface of the porous electrode;

drying the deposited mixture at about 300° C.;

high temperature annealing for removal of all the impurities andcrystallization of the yttrium-doped zirconium dioxide.

Disadvantages of this method are the strong dependence of the propertiesof the thus obtained electrolyte layer on the initial mixturepolymerization degree and viscosity; poor adhesion to the electrodematerial; high content of impurities that impair the electrochemicalproperties of the electrolyte and the electrode-electrolyte pair; poorreproducibility of the method due to the complex chemical processes usedfor the production of the polymer solution; insufficient adaptability ofthe method with respect to the choice of electrolyte composition and thematerial and properties of the electrode.

Known also is an electrolyte film fabrication method from yttrium-dopedcerium dioxide produced from cerium nitrate solution and yttriumchloride in a mixture of ethanol and butylcarbitol (50:50 vol. %) byspraying the aerosol onto the yttrium-stabilized Ni—ZrO₂ anode substrateheated to 250-300° C. (D. Perednis, L. J. Ganckler SOFCs with thinelectrolyte films deposited by spray pyrolysis, 5^(th) European SolidOxide Fuel Cell Forum, 2002, Lucerne/Switzerland, Proceedings, pp.72-75).

However, this method allows producing only very thin yttrium-dopedcerium dioxide films in the structure of the cerium dioxide basedtwo-layered electrolyte.

Known is an electrode-electrolyte pair fabrication method by depositinga coating containing gadolinium-doped cerium dioxide onto the electrodeusing a colloid solution of doped cerium dioxide fine particles in anorganic polymer (H. U. Anderson, V. Petrowsky Thin film zirconia andceria electrolytes for low temperature SOFCs, 5^(th) European SolidOxide Fuel Cell Forum, 2002, Lucerne/Switzerland, Proceedings, pp.240-247).

This method is very suitable for the deposition of electrolyte powder onthe electrode surface, but, in fact, the electrolyte layer forms on theelectrode in this method due to electrolyte material powder sinteringafter the removal of the organic polymer. Even at very small powder size(5 nm) and its high sintering activity, the films have a porosity of20%, and densening to 95% of the theoretical density occurs only at1000° C. As a result, the electrochemical properties of the electrolyteand the electrode-electrolyte pair are low.

Known is the colloid solution used in method (H. U. Anderson, V.Petrowsky Thin film zirconia and ceria electrolytes for low temperatureSOFCs, 5^(th) European Solid Oxide Fuel Cell Forum, 2002,Lucerne/Switzerland, Proceedings, pp. 240-247).

With all the technical advantages of this solution for the formation ofa uniform powdered layer on the surface to be coated, an obviousdisadvantage of colloid solutions is that the organic polymer does notcontribute to the formation of the electrolyte dense structure. Thenecessity of sintering leads to unavoidable settling of the film andhence large stresses that promote cracking in the electrolyte layer atthe electrolyte-electrode boundaries.

DISCLOSURE OF THE INVENTION

The technical objective of the invention is the production of a low-costelectrode-electrolyte pair having an elevated electrochemical efficiencyas the most important structural part of a highly efficient,economically advantageous and durable fuel cell.

Each of the inventions included into the group is aimed at achieving aseparate additional objective.

More particularly, the electrode-electrolyte pair embodiment shown asthe first and the fourth objectives of the invention in the suggestedgroup of inventions achieve additional technical objectives comprising:

reduction of the working temperature of the electrochemical devicecomprising the electrode-electrolyte pair;

increasing the operation efficiency and reliability of theelectrode-electrolyte pair;

reduction of the dimensions and weight per unit power generated by thefuel cell comprising the electrode-electrolyte pair;

adaptability of the design, materials and dimensions of the electrode.

Furthermore, the electrode-electrolyte pair fabrication methods shown asthe second and fifth objectives of the invention in the suggested groupof inventions achieve additional technical objectives comprisingincreasing the technological suitability of the method for commercialfabrication of the electrode-electrolyte pair, increasing thefabrication efficiency and reduction of the cost of theelectrode-electrolyte pair and the entire electrochemical device,reduction of power consumption and increasing the adaptability of themethod.

Furthermore, the organogel comprised in the components used for thefabrication of the first embodiment of the electrode-electrolyte pairand shown as the third objective of the invention in the suggested groupof inventions achieves additional technical objectives comprisingreducing the cost of the organogel, increasing its adaptability,increasing its adhesion to the electrode material and avoidingelectrolyte contamination with detrimental impurities.

Below, embodiments of the electrode-electrolyte pair design,electrode-electrolyte pair fabrication methods and materials used aredisclosed in accordance with the invention claimed herein that achievesaid technical objective.

The first embodiment of the electrode-electrolyte pair comprises amicroporous electrode to the surface of which is deposited amultilayered solid electrolyte based on zirconium dioxide withstabilizing additions. The solid electrolyte consists of the innernano-porous three-dimensional solid electrolyte layer. The grain size ofthis electrolyte layer is within 1000 nm. The inner layer fills, atleast partially, the surface pores of the microporous electrode to adepth of 5-50 μm. On the surface of the inner layer there is a denseouter electrode layer. The grain size of this electrolyte layer is alsowithin 1000 nm.

In a specific embodiment, the inner and outer electrolyte layers mayhave similar or different compositions.

In some embodiments, the inner electrolyte layer has a combinedamorphous and nanocrystalline structure.

Moreover, in a specific embodiment, the outer electrolyte layer has anamorphous structure.

Moreover, in specific embodiments, as the stabilizing additions, thesolid electrolyte contains magnesium and/or calcium and/or yttriumand/or scandium and/or aluminum and/or rare earth metals and/ortitanium.

In a specific embodiment, the electrode is in a microporous ceramic ormetallic or metalloceramic material with pore sizes of above 1 μm.

Moreover, in a specific embodiment, the electrode of the pair is anodeor cathode with a flat or pipe-like shape.

In a specific embodiment, the anode is made of a volume mesh or a foammaterial.

The electrolytic efficiency of the electrode-electrolyte pair and theentire electrochemical device is increased due to the followingadvantages:

increasing the lateral conductivity of the electrolyte due to theoptimization of the outer and inner cerium dioxide layers by doping;

increasing the electric contact area of the electrolyte with theelectrode material due to the use of the inner surface of electrodepores;

reduction of the electrical resistivity at the electrode-electrolyteboundary due to the low electrode deposition temperatures;

increasing the electrochemical contact area of the gaseous phase, theelectrode and the electrolyte due to the nanoporous inner electrolytelayer and the surface conductivity.

Reduction of the working temperature of the electrochemical deviceconsisting of the electrode-electrolyte pair is achieved due to theabove advantages and the possibility of producing a dense electrolytelayer having a minimum thickness.

Increasing the operation efficiency and reliability of theelectrode-electrolyte pair is achieved due to the high strength of theamorphous and nanocrystalline structure of cerium dioxide; eliminationof the surface stress concentrators in the electrode due to thenanoporous inner electrode layer; the high damping capacity of the innernanoporous and the three-dimensional electrolyte layers that avoidcracking in the electrolyte.

As is well known, the cost, dimensions and weight of an electrochemicalgenerator consisting of fuel cells are determined as per unit generatedpower. Therefore any increase in the electrochemical efficiency of theelectrode-electrolyte pair reduces the cost, dimensions and weight. Forexample, in the generation of 1 kW of electric power, an increase in theunit power from 0.25 W/cm² to 1 W/cm² results in a 4-fold costreduction, decrease in the dimensions, i.e. fuel cell area, from 0.4 m²to 0.1 m² and a 4-fold weight reduction.

The increase in the adaptability of the device technology is achieveddue to the possibility of using electrodes having a porosity of above 1μm made from ceramic, metalloceramic and metallic materials, in the formof a cathode or anode having a flat or pipe shape.

The electrode-electrolyte pair fabrication method based on ceriumdioxide following the first embodiment of the invention comprises theformation, on the microporous electrode surface, of a partiallyelectrode-penetrating multilayered solid electrolyte based on ceriumdioxide with stabilizing additions. During the formation, themicroporous electrode surface is initially impregnated with organogelconsisting of particles of cerium dioxide with stabilizing additions andan organic solution containing organic salts of cerium and thestabilizing metals. The next step is destruction of the organogelorganic part that leads to the chemical deposition of the innernanoporous three-dimensional solid electrolyte layer on the electrodesurface. Then, the inner organogel layer is deposited onto the surface,said layer consisting of nanosized particles of cerium dioxide withstabilizing additions and an organic solution containing organic saltsof cerium and the stabilizing metals. The next step is destruction ofthe organogel organic part that leads to the chemical deposition of thedense outer layer of the multilayered electrolyte onto the inner layersurface.

In a specific embodiment, the organogel used for the formation of theinner and outer solid electrolyte layers can be of similar or differentcompositions.

In specific embodiments, the stabilizing additions for the solidelectrolyte according to this method can be yttrium and/oralkaline-earth metals and/or rare earth metals and/or bismuth.

In a specific embodiment, the microporous electrode surface isimpregnated with organogel in vacuum or by mechanical pressing theorganogel into the microporous surface of the electrode.

Moreover, in a specific embodiment, destruction is performed byhigh-energy impact that causes the decomposition of the organic part ofthe organogel, e.g. thermal, induction or infrared heating, or electronor laser beam impact or plasmachemical impact.

Also, in a specific embodiment, organogel destruction is performed withhigh-rate pyrolysis at temperatures within 800° C. in an oxidizing,inert or weakly reducing gas atmosphere.

In specific embodiments, organogel organic part destruction is performedsimultaneously or in sequence, by organogel impregnation or depositionto the inner layer surface.

In a specific embodiment, during organogel impregnation of the electrodeor organogel deposition to the inner layer surface with simultaneousdestruction, the organogel is deposited to the surface to be coated byspraying or printing.

In a specific embodiment, during organogel impregnation of the electrodeor organogel deposition to the inner layer surface with subsequentdestruction, the organogel is deposited to the cold surface of theelectrode or the inner layer with subsequent high-rate heating of theelectrode.

In a specific embodiment, organogel impregnation of the electrode ororganogel deposition to the inner layer surface and organogeldestruction are performed in one or multiple steps.

Said technical result is achieved due to the high rate of materialdeposition and electrolyte formation on the electrode surface;possibility of using simple and cheap equipment, use of lowtemperatures, possibility of setting up the technological process in acompletely automatic conveyor embodiment; method adaptability withrespect to electrolyte composition choice; method adaptability withrespect to electrode-electrolyte pair design choice; possibility oftaking the properties and parameters of the electrode materials intoaccount.

The organogel used for the fabrication of the electrode-electrolyte paircontains nanosized particles of cerium dioxide with stabilizingadditions and an organic solution containing organic salts of cerium andthe stabilizing metals, a mixture of α-branching carbonic acids with thegeneral formula H(CH₂—CH₂)_(n)CR′R″—COOH, where R′ is CH₃, R″ isC_(m)H_((m+1)) and m is from 2 to 6, with an average molecular weight of140-250.

In a specific embodiment, the stabilizing metals used for the organogelare yttrium and/or alkaline-earth metals and/or rare earth metals and/orbismuth.

Moreover, in a specific embodiment, as the organic solvent, theorganogel contains carbonic acid and/or any organic solvent of carbonicacid metal salts.

In a specific embodiment, the organogel contains nanosized particlesfrom 3 to 100 nm.

In specific embodiments, the concentration of stabilizing additions inzirconium and metal salts in the organogel is selected at 0.05 to 1mole/l in a ratio corresponding to the electrolyte stoichiometriccomposition.

Specifically, the volume ratio of the nanosized particles in theorganogel is within 85%.

The second embodiment of the electrode-electrolyte pair comprises ananoporous electrode to the surface of which is deposited a layer ordense three-dimensioned electrolyte based on zirconium dioxide withstabilizing additions the grain size of which is within 1000 nm. Theelectrolyte fills the surface pores of the nanoporous electrode to adepth of 1-5 μm.

In a specific embodiment, the electrolyte has an amorphous structure.

In a specific embodiment, as the stabilizing additions, theelectrode-electrolyte pair contains yttrium and/or alkaline-earth metalsand/or rare earth metals and/or bismuth.

In specific embodiments, the electrode of the pair is anode or cathodewith a flat or pipe shape.

The electrode is in a microporous ceramic or metallic or metalloceramicmaterial with pore sizes, at least near the surface, of within 1 μm. Inthis embodiment of the electrode-electrolyte pair, the electrode mayhave a functional or technological sublayer on the surface. Thissublayer can be in a nanoporous cathodic or anodic material, anotherelectrolyte material or a fine-grained mixture of the electrode and theelectrolyte materials.

The electrode-electrolyte pair fabrication method based on ceriumdioxide following the second embodiment of the invention comprises theformation, on the microporous electrode surface, of a densethree-dimensional solid electrolyte layer based on cerium dioxide withstabilizing additions. During the formation, the nanoporous electrodesurface is initially impregnated with an organic solution containingorganic salts of cerium and the stabilizing metals, a mixture ofbranching carbonic acids with the general formulaH(CH₂—CH₂)_(n)CR′R″-COOH, where R′ is CH₃, R″ is C_(m)H_((m+1)) and m isfrom 2 to 6, with an average molecular weight of 140-250. The next stepis destruction of the solution organic part that leads to the chemicaldeposition of the solid electrolyte on the electrode surface.

In specific embodiments, the stabilizing additions for the solidelectrolyte according to this method can be yttrium and/oralkaline-earth metals and/or rare earth metals and/or bismuth.

Moreover, in a specific embodiment, as the organic solvent, the solutioncontains carbonic acid or toluene or octanol or any organic solvent ofcarbonic acid metal salts.

Moreover, in a specific embodiment, destruction is performed byhigh-energy impact that causes the decomposition of the organic part ofthe solution, e.g. thermal, induction or infrared heating, or electronor laser beam impact or plasmachemical impact.

In specific embodiments, solution destruction is performed withhigh-rate pyrolysis at temperatures within 800° C. in an oxidizing,inert or weakly reducing gas atmosphere.

In a specific embodiment, solution organic part destruction is performedsimultaneously or in sequence, with impregnation.

Specifically, during electrode impregnation with simultaneousdestruction, the solution is deposited to the surface to be coated byspraying or printing.

In a specific embodiment, during electrode impregnation with subsequentdestruction, the solution is deposited to the cold surface of theelectrode with subsequent high-rate heating of the electrode.

Also, in a specific embodiment, the concentration of stabilizingadditions in zirconium and metal salts in the solution is selected at0.05 to 1 mole/l in a ratio corresponding to the electrolytestoichiometric composition.

Moreover, in a specific embodiment, solution deposition onto theelectrode or destruction are performed in one or multiple steps.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows schematic of one embodiment of the electrode-electrolytepair according to the invention.

FIG. 2 shows schematic of another embodiment of theelectrode-electrolyte pair.

EMBODIMENTS OF THE INVENTION

The electrode-electrolyte pair (FIG. 1) comprises a microporouselectrode 1 with pores 2, an inner nanoporous three-dimensional solidelectrolyte layer 3 and a dense outer solid electrolyte layer 4.

The efficiency of a fuel cell (electrical power generated per unitsurface) is determined by the following factors:

ionic conductivity of the electrolyte based on cerium dioxide (thehigher the conductivity, the greater the power available);

electrolyte layer thickness (the greater the thickness, the greater thepower);

electrical resistivity at the electrode-electrolyte boundary (the lowerthe resistivity, the greater the power);

contact area between the electrode and the electrolyte (the greater thearea, the greater the power);

electrochemical contact area of the gaseous phase, the electrode and theelectrolyte (the greater the electrochemical contact area, the greaterthe power).

The operation efficiency of the electrode-electrolyte pair is mainlydetermined by the density of the zirconium dioxide electrolyte layer(absence of through pores and macrocracks) and its ability to resistthermal stresses both during the fabrication and during the operation ofthe fuel cell. The latter quality of the electrolyte layer materialdepends on the strength of the material, electrolyte adhesion to theelectrode material and the ability of the electrode-electrolyte pair torelieve mechanical stresses without forming cracks, taking into accountthe role of the surface stress concentrators on theelectrode-electrolyte boundary.

Thus, the efficiency of the electrode-electrolyte pair, is determined bythe composition of metal-doped cerium dioxide, its mechanical propertiesunder the condition of their maximum matching with the mechanicalproperties of the electrode and the design of the cerium dioxide layeron the porous electrode surface.

The possibility of achieving the optimum properties and parameters of anelectrode-electrolyte pair is determined by its fabrication method.

As the electrolyte material for fuel cells, metal-doped cerium dioxideis used. As the doping metals, yttrium and/or alkaline-earth metalsand/or rare-earth metals are used.

Doping allows producing stabilized cerium dioxide having a cubicfluoride structure. Moreover, doping allows producing cerium dioxide ofcombined conductivity that can be used as a sublayer on the cathode oranode for reducing the electrical resistivity at theelectrode-electrolyte boundary.

According to this embodiment of the invention (FIG. 1) electrode 1 canhave a flat or pipe shape, act as a cathode or an anode and be made froma ceramic, metallic or metalloceramic material with a pore size of above1 μm. For example, anode can be made from metals, such as nickel, cobaltor their alloys and stainless steels; metalloceramics, such asNiO(Ni)-stabilized zirconium dioxide, NiO(Ni)-stabilized cerium dioxide,CoO(Co)-stabilized zirconium dioxide or CoO(Co)-stabilized ceriumdioxide. A metallic anode can be made from foam metal or a volume mesh.Ceramic cathode can be made from perovskite family ceramics, such asLaMnO₃, LaCoO₃, LaNiO₃, lanthanum gallates and other metal oxides havinga good electronic conductivity and catalytic activity to ionize airoxygen. Cathode can be made from metal with a protective oxide coating.Electrode porosity is typically 20 to 80%.

The inner nanoporous three-dimensional layer 3 consisting of stabilizedzirconium dioxide penetrates into the porous electrode 1 to a depth of5-50 μm. The stabilizing metals can be yttrium and/or alkaline-earthmetals and/or rare earth metals and/or bismuth.

The penetration depth (H) depends on electrode pore diameter (D),typically as H=(2-3) D.

The key problem of thin electrolyte layer efficiency and reliability,however produced, is its defectiveness, i.e. the presence of pores andmicrocracks, as well as poor adhesion. The main origin of this problemare the high thermal and internal stresses both in the electrolyteitself and on the phase boundary. During electrode deposition onto theporous surface of electrode 1, the surface microroughnesses act asstress concentrators thus leading to crack initiation even at relativelylow thermal and internal stresses.

In the invention disclosed herein, of extreme importance is the innernanoporous three-dimensional electrolyte layer 3 made from stabilizedzirconium dioxide. For example, due to the penetration of the layer 3into the electrode 1, its nanoporousity and the good adhesion to thematerials of the electrode 1, the surface stress concentrators areeliminated, the electrode and electrolyte thermal expansion coefficientsare matched and the mechanical stresses are relieved. The above effectsbecome even stronger if the inner layer 3 has a porosity gradient, i.e.an increase in porosity from the electrode surface downwards. Thesefactors tangibly increase the reliability and operation efficiency ofthe electrode-electrolyte pair, primarily expressed in the prevention ofcracking and defect formation in the dense layer 4. Moreover, thisadvantage provides for the minimization of the thickness of the denselayer 4, thus reducing the working temperature of the electrochemicaldevice and an increase in its electrochemical efficiency.

For example, the suggested inner layer 3 consisting of tetragonal ceriumdioxide can relieve stresses of up to 500 MPa when in combination with aceramic electrode and up to 1000 MPa when in combination with a metallicelectrode.

The high strength and cracking resistance of the inner layer 3 that areof primary importance for the fabrication of the electrode-electrolytepair are achieved due to the three dimensions and the specific combinedstructure consisting of 3-1000 nm grains and an amorphous phase.

In the invention disclosed herein, the role of the inner nanoporousthree-dimensional layer 3 consisting of stabilized cerium dioxide isimportant also from the viewpoint of increasing the electrochemicalefficiency of the electrode-electrolyte pair. First, this is due to themultiple increase in the area of the electrical contact between the thematerial of layer 3 and the material of electrode 1. Second, thenanocrystalline layer 3 has a higher conductivity of oxygen ions. Forexample, the oxygen ion conductivity of a nanocrystalline layer (grainsize 10-100 nm) of Ce_(0.8)Sm_(0.2)O₂ electrolyte is 2-3 times that ofthe same composition electrolyte with a grain size of 20 μm.

Third, the nanoporous layer 3 has a high surface ionic and electronicconductivity, especially in a wet gaseous atmosphere at the side of theelectrode 1. Fourth, doping of stabilized cerium dioxide that composesthe inner layer 3, e.g. with gadolinium, produces a combined type ofconductivity in the layer 3 thereby multiply increasing the area of theelectrochemical contact between the ionic conductor, the electronicconductor and air oxygen (for cathodic electrode) or the fuel (foranodic electrode).

Thus, the inner layer 3 provides for a high current density, a low levelof electrode overstressing and a high specific power of the fuel cell asa whole.

The dense layer 4 of solid electrolyte is a thin two-dimensional layerconsisting of cubic cerium dioxide that has a 100% ionic type ofconductivity. Stabilizing metals can be calcium, magnesium, yttrium,scandium and aluminum. Due to the layer 4 localization on the surface ofthe inner nanoporous layer 3 that eliminates the surface stressconcentrators and relieves all the technological and thermal stresses,it may be up to 0.5-5 μm in thickness. Due to this fact, the ohmiclosses in the electrolyte are minor, providing for a highelectrochemical efficiency of the electrolyte as is. The amorphousstructure of the layer 4 provides for its strength and elasticity thatare important at the electrode-electrolyte pair fabrication stage wherethe reject percentage is known to be the highest. This advantageindirectly reduces the cost of the electrode-electrolyte pair and theelectrochemical device as a whole. After the deposition of theelectrolyte layer 4 the amorphous structure of zirconium dioxide can becrystallized without the risk of cracking in the layer.

The compositions of the layers 3 and 4 can be similar or different. Thecomposition and properties may exhibit a gradient behavior across thelayers 3 and 4. This can be achieved by sequential deposition of thelayers 3 and 4 with an appropriate change in the technologicalconditions and the materials used. This feature broadens the potentialcapabilities of the pair and its technology. Moreover, where one of theelectrolyte layers should have special properties, cerium dioxide can bedoped with multiple different metals. For example, additional scandiumand aluminum doping of stabilized cerium dioxide increases the strengthof the electrolyte as compared with undoped cerium dioxide.Stabilization of cerium dioxide by bismuth doping increases the densityand ionic conductivity of the electrolyte. Yttrium-stabilized ceriumdioxide after additional strontium doping acquires reduction stability,this significantly increasing the efficiency of the anode-electrolytepair.

The second electrode-electrolyte pair embodiment (FIG. 2) comprises ananoporous electrode 5 with pores 6 and a dense three-dimensional solidelectrolyte layer 7.

According to this electrode-electrolyte pair embodiment, the electrode 5can have flat or pipe shape, act as a cathode or an anode and be inceramic, metallic or metalloceramic materials. A currently generallyused embodiment of the electrode 5 is a cathode with a cathodic orelectrolyte sublayer or an anode with an anodic or electrolyte sublayer.The pores 6 of the electrode or the sublayer are less than 1 μm in size.

The dense three-dimensional dense electrolyte layer 7 consisting ofstabilized cerium dioxide is located on the electrode surface andpartially penetrates into the pores 6 to a depth of 1-5 μm. The denseelectrolyte layer 7 is cubic cerium dioxide stabilized with yttrium orrare-earth metals. Moreover, additional doping of stabilized ceriumdioxide with other metals. The layer 7 has an amorphous structure, atleast at the deposition stage. This layer has the same functions and thesame advantages as the double layer according to the first embodiment ofthe electrode-electrolyte pair, the only difference being in that for anelectrode pore size of less than 1 μm there is no need to deposit ananoporous inner electrolyte layer.

The first embodiment of the electrode-electrolyte pair suggested anddisclosed herein (FIG. 1) is fabricated using the first suggestedfabrication method and the suggested organogel.

The organogel is a metalorganic liquid consisting of an organic solutionof cerium and alloying metal organic salts with an addition of nanosizeparticles of stabilized cerium dioxide. The organic basis of the metalsalts is a mixture of α-branching carbonic acids with the generalformula H(CH₂—CH₂)_(n)CR′R″—COOH, where R′ is CH₃, R″ is C_(m)H_((m+1))and m is from 2 to 6, with an average molecular weight of 140-250. Theorganic salt solvent is carbonic acid and/or any other organic solventof carbonic acids, e.g. toluene, octanol etc. The main function of thesolvent is to adjust the viscosity of the organogel.

The salts of cerium and alloying metals, such as yttrium, rare-earthmetals, bismuth, aluminum, alkaline and alkaline-earth metals, areobtained by extraction from water solutions of appropriate metal saltsto a mixture of carbonic acid, following which the metal carboxylatesare mixed in the proportion as is required for the production of thefinal electrolyte stoichiometric composition. The concentration of eachmetallic element in the carboxylates may vary from 0.05 to 1.0 mole/l.

The material of the nanosized particles is stabilized and/or dopedcerium dioxide. The size of the nanoparticles corresponding to theelectrolyte composition or part of the electrolyte composition is 3 to100 nm. The volume ratio of the particles in the organogel may reach 85%of the total organic liquid volume. The volume ratio of the particles inthe organogel controls the organogel viscosity and the density of theelectrolyte layer deposited. The higher the particles content, thehigher the organogel viscosity and the nanoporosity of the electrolytelayer deposited. The rule for determining the optimum volume ratio ofthe particles in the organogel is as follows: the greater the electrodepore size, the greater the volume ratio of the particles. Organogel isproduced by mechanically mixing the particles and the organic liquid.

The electrolyte layer production method is based on destruction(decomposition) of the organogel organic component deposited on theelectrode surface. An oxide layer forms on the surface, composed of theparticles and oxides of the metals chemically deposited from appropriatemetal carboxylates in the organogel composition. Oxides of metalsdeposited from carboxylates cement the particles between themselves toform a monolithic structure. Unlike other solution deposition methodsthat produce metal oxide powders on the surface that needhigh-temperature sintering, the method disclosed herein allows directproduction of a compact electrolyte layer at low temperatures, thisbeing a fundamental distinctive feature of the method.

The difference is attributed to the property of metal oxides depositedfrom carboxylates to have an amorphous structure during destruction. Anamorphous structure is a solid counterpart of liquids, and, by analogywith liquid electrolytes, it has the following advantages:

it provides for the greatest possible area of electrochemical contactbetween the zirconium dioxide deposited electrolyte and the electrodematerials;

it inherits the microroughnesses of the electrode surfaces, includingthe surface of their open pores;

it covers the open pores and microcracks on the surface of electrodes.

Moreover, sequential transition from the liquid state of the organogelto a crystalline zirconium oxide structure through an intermediateamorphous state allows optimizing some useful properties of theelectrolyte, such as adhesion, internal stresses and diffusioninteraction at phase boundaries.

Stages of electrolyte formation on a microporous surface are as follows.

The first stage is deposition of the organogel onto the surface of theporous electrode using any known method. During the synthesis of theinner nanoporous three-dimensional electrolyte layer, the depositionincludes impregnation of the surface pores of the electrodes with theorganogel. The impregnation is performed by mechanical pressing of theorganogel into the porous surface of the electrode, e.g. with a paintroller, or by vacuum impregnation. Vacuum impregnation is preferablyused for small pore electrodes. For the production of the dense outerelectrolyte layer, the organogel is deposited by spraying or printing.

The second stage is destruction (decomposition) to produce anelectrolyte layer on the surface and remove the organic components in agaseous state.

The two above process stages can be unified by depositing the organogelonto the heated electrode surface by spraying or printing, provided thesurface temperature is sufficient for destruction.

The electrolyte layer can be synthesized using any process that causesdestruction of the organic part of the organogel, e.g. thermal,induction or infrared heating, or electron or laser beam impact orplasmachemical impact.

The simplest and cheapest method from the technological and economicalviewpoints is thermal destruction (pyrolysis). The destruction onsettemperature for the organogel is about 200° C. The process can beconducted under atmospheric pressure in air or in an inert or weaklyreducing gas atmosphere. The temperature and the gas atmospheredetermine the destruction rate and hence electrolyte properties.Stabilization of the intermediate amorphous state is preferablyperformed in an inert or weakly reducing gas atmosphere or usinghigh-rate destruction methods. The minimum electrolyte layer formationtime is 30 seconds.

For example, an electrolyte layer can be synthesized by heating theelectrode in an inert or weakly reducing gas atmosphere to within 800°C. and depositing the organogel onto the surface by spraying.High-temperature impregnation of the electrode surface pores occursimmediately upon the incidence of the organogel onto the surface. Duringdestruction, the organic part of the organogel decomposes to volatilecomponents, whereas the surface, including the surface pores, becomescovered with oxides that form the electrolyte layer. During the seconddeposition of the organogel the electrolyte layer forms on the surfaceof the first deposited layer. The density and properties of the outerelectrolyte layer are determined by the organogel composition andproperties.

Organogel can be deposited onto the cold electrode surface for furtherdestruction. For thermal destruction, the temperature should also bewithin 800° C.

The final synthesis of crystalline electrolyte from the already formedamorphous material layer implies final air heat treatment. Preferably,the heat treatment temperature should not exceed the working temperatureof the electrochemical device by more than 10-15%.

Organogel properties, such as particle composition, metal compositionand concentrations in the organic salt mixture, and the volume ratios ofthe particles and the carboxylate solution are chosen depending on thefinal electrolyte composition, thickness, substrate surface propertiesetc. These organogel properties allow controlling all the electrolyteparameters with due regard to the substrate surface properties.

The method allows producing electrolyte films on substrates of anymaterials, shapes and sizes.

The method is very efficient and cost-effective.

The method is easily adaptable to complete automation and conveyorfabrication setup.

The low electrolyte layer synthesis temperatures provide for yet anotherfundamental advantage in comparison with the other known methods. Thisadvantage is the absence of chemical interaction between the electrolyteand the electrode materials. This results in the absence of highlyelectrically resistant oxides on the phase boundary and hence providesfor a significant increase in current density and specific power of thefuel cell.

Below, the possibilities of the first electrode-electrolyte pairembodiment fabrication method (FIG. 1) and the organogel for this methodwill be illustrated with specific examples that do not limit the scopeof this invention.

EXAMPLE 1

Organogel for the production of electrolyte of the CeO₂—Sm₂O₃ system,e.g., (CeO₂)_(0.8)(SmO_(1.5))_(0.2).

EXAMPLE 1.1

Ce and Sm carboxylates with concentrations of 1.0-1.5 mole/l areproduced by extraction of water salts of cerium and samarium to amixture of acids with the general formula H(CH₂—CH₂)_(n)CR′R″—COOH,where R′ is CH₃, R″ is C_(m)H_((m+1)) and m is from 2 to 6, with anaverage molecular weight of 140-250. The excess quantity of carbonicacids act as solvent. Ce and Sm carboxylates are mixed in proportionscorresponding to the stoichiometric composition of the (CeO₂)_(0.8)(SmO_(1.5))_(0.2) electrolyte.

The carboxylate solution is mixed with 3-100 nm sized nanometricparticles with the (CeO₂)_(0.8) (SmO_(1.5))_(0.2) composition. Thevolume ratio of the nanometric particles is 85% of the organic liquidvolume.

Organogel according to Example 1.1 is used for the production of theinner nanoporous three-dimensional (CeO₂)_(0.8) (SmO_(1.5))_(0.2)composition electrolyte layer on metallic, metalloceramic or ceramicelectrodes with pore sizes from 5 to 30 μm and penetration depth intothe electrode of 10 to 60 μm, respectively.

EXAMPLE 1.2

Solution of Ce and Sm carboxylates with concentrations of 1.0-1.5 mole/las in Example 1.1 is produced. Ce and Sm carboxylates are mixed inproportions corresponding to the stoichiometric composition of the(CeO₂)_(0.8) (SmO_(1.5))_(0.2) electrolyte. The carboxyl ate solution ismixed with 3-100 nm sized nanometric particles with the (CeO₂)_(0.8)(SmO_(1.5))_(0.2) composition. The volume ratio of the nanometricparticles is 5-20% of the organic liquid volume.

Organogel according to Example 1.2 is used for the production of thedense outer (CeO₂)_(0.8) (SmO_(1.5))_(0.2) composition electrolyte layeron the surface of the inner nanoporous three-dimensional electrolytelayer based on doped cerium dioxide or on the surface of any othersublayer.

EXAMPLE 1.3

Solution of Ce and Sm carboxylates with concentrations of 0.05 mole/lcorresponding to the stoichiometric composition of the (CeO₂)_(0.8)(SmO_(1.5))_(0.2) electrolyte as in Example 1.1 is produced.

The carboxylate solution corresponding to the (CeO₂)_(0.8)(SmO_(1.5))_(0.2) composition is mixed with 3-100 nm sized nanometricparticles with the (CeO₂)_(0.8) (SmO_(1.5))_(0.2) composition. Thevolume ratio of the nanometric particles is 5-20% of the organic liquidvolume.

Organogel according to Example 1.3 is used for the production of theinner nanoporous three-dimensional (CeO₂)_(0.8) (SmO_(1.5))_(0.2)composition electrolyte layer on metallic, metalloceramic or ceramicelectrodes with pore sizes from 1 to 5 μm and penetration depth into theelectrode of 3 to 15 μm, respectively.

EXAMPLE 1.4

Solution of Ce and Sm carboxylates with concentrations of 0.05 mole/l asin Example 1.1 corresponding to the (CeO₂)_(0.8) (SmO_(1.5))_(0.2)composition is produced.

The carboxylate solution corresponding to the (CeO₂)_(0.8)(SmO_(1.5))_(0.2) composition is mixed with 3-100 nm sized nanometricparticles with the (CeO₂)_(0.8) (SmO_(1.5))_(0.2) composition,respectively. The volume ratio of the nanometric particles is 1 to 10%of the organic liquid volume.

Organogel according to Example 1.4 is used for the production of thedense outer (CeO₂)_(0.8) (SmO_(1.5))_(0.2) composition electrolyte layeron the surface of the inner nanoporous three-dimensional electrolytelayer based on doped cerium dioxide or on the surface of any othersublayer.

EXAMPLE 2

Organogel for the production of electrolyte of the CeO₂—Gd₂O₃, e.g.,(CeO₂)_(0.8) (GdO_(1.5))_(0.2) systems.

EXAMPLE 2.1

Ce and Gd carboxylates with concentrations of 0.5-1.5 mole/l areproduced by extraction of water salts of cerium and samarium to amixture of carbonic acids with the general formulaH(CH₂—CH₂)_(n)CR′R″—COOH, where R′ is CH₃, R″ is C_(m)H_((m+1)) and m isfrom 2 to 6, with an average molecular weight of 140-250. The excessquantity of carbonic acids act as solvent. Ce and Gd carboxylates aremixed in proportions corresponding to the stoichiometric composition ofthe (CeO₂)_(0.8) (GdO_(1.5))_(0.2) electrolyte.

The carboxylate solution is mixed with 3-100 nm sized nanometricparticles with the (CeO₂)_(0.8) (GdO_(1.5))_(0.2) composition. Thevolume ratio of the nanometric particles is 40-60% of the organic liquidvolume.

Organogel according to Example 2.1 is used for the production of theinner nanoporous three-dimensional (CeO₂)_(0.8) (GdO_(1.5))_(0.2)composition electrolyte layer on metallic, metalloceramic or ceramicelectrodes with pore sizes from 3 to 10 μm and penetration depth intothe electrode of 6 to 20 μm, respectively.

EXAMPLE 2.2

Solution of Ce and Gd carboxylates with concentrations of 0.5-1.5 mole/las in Example 2.1 is produced.

The carboxylate solution is mixed with 3-100 nm sized nanometricparticles with the (CeO₂)_(0.8) (GdO_(1.5))_(0.2) composition.

The volume ratio of the nanometric particles is 1-20% of the organicliquid volume.

Organogel according to Example 2.2 is used for the production of thedense outer (CeO₂)_(0.8) (GdO_(1.5))_(0.2) composition electrolyte layeron the surface of the inner nanoporous three-dimensional electrolytelayer based on doped cerium dioxide or on the surface of any othersublayer.

EXAMPLE 3

Organogel for the production of electrolyte of the CeO₂—Y₂O₃, e.g.,(CeO₂)_(0.8) (YO_(1.5))_(0.2) systems.

EXAMPLE 3.1

Ce and Y carboxylates with concentrations of 1.5 mole/l are produced byextraction of water salts of cerium and yttrium to a mixture of carbonicacids with the general formula H(CH₂—CH₂)_(n)CR′R″—COOH, where R′ isCH₃, R″ is C_(m)H_((m+1)) and m is from 2 to 6, with an averagemolecular weight of 140-250. The excess quantity of carbonic acids actas solvent. Ce and Y carboxylates are mixed in proportions correspondingto the stoichiometric composition of the (CeO₂)_(0.8) (YO_(1.5))_(0.2)electrolyte.

The carboxylate solution is mixed with 3-100 nm sized nanometricparticles with the (CeO₂)_(0.8) (YO_(1.5))_(0.2) composition. The volumeratio of the nanometric particles is 50-85% of the organic liquidvolume.

Organogel according to Example 3.1 is used preferably for the productionof the inner nanoporous three-dimensional (CeO₂)_(0.8) (YO_(1.5))_(0.2)composition electrolyte layer on metallic, metalloceramic or ceramicelectrodes with pore sizes from 5 to 30 μm and penetration depth intothe electrode of 10 to 60 μm, respectively.

EXAMPLE 3.2

Solution of Ce and Y carboxylates with concentrations of 0.05-0.5 mole/las in Example 3.1 is produced. Ce and Y carboxylates are mixed inproportions corresponding to the stoichiometric composition of the(CeO₂)_(0.8) (YO_(1.5))_(0.2) electrolyte.

The carboxylate solution is mixed with 3-100 nm sized nanometricparticles with the (CeO₂)_(0.8) (YO_(1.5))_(0.2) composition.

The volume ratio of the nanometric particles is 5-25% of the organicliquid volume.

Organogel according to Example 3.2 is used preferably for the productionof the dense outer (CeO₂)_(0.8) (YO_(1.5))_(0.2) composition electrolytelayer on the surface of the inner nanoporous three-dimensionalelectrolyte layer based on doped cerium dioxide or on the surface of anyother sublayer.

EXAMPLE 4

Organogel for the production of electrolyte of the[(Y_(0.5)Sr_(0.5))_(0.4)Ce_(0.6)]O_(x) composition.

EXAMPLE 4.1

Ce, Sr and Y carboxylates with concentrations of 0.5-1.5 mole/l areproduced by extraction of water salts of cerium, strontium and yttriumto a mixture of carbonic acids with the general formulaH(CH₂—CH₂)_(n)CR′R″—COOH, where R′ is CH₃, R″ is C_(m)H_((m+1)) and m isfrom 2 to 6, with an average molecular weight of 140-250. The excessquantity of carbonic acids act as solvent. Ce, Sr and Y carboxylates aremixed in proportions corresponding to the stoichiometric composition ofthe [(Y_(0.5)Sr_(0.5))_(0.4)Ce_(0.6)]O_(x) electrolyte.

The carboxylate solution is mixed with 3-100 nm sized nanometricparticles with the [(Y_(0.5)Sr_(0.5))_(0.4)Ce_(0.6)]O_(x) composition.The volume ratio of the nanometric particles is 50-85% of the organicliquid volume.

Organogel according to Example 4.1 is used preferably for the productionof the inner nanoporous three-dimensional[(Y_(0.5)Sr_(0.5))_(0.4)Ce_(0.6)]O_(x) composition electrolyte layer onmetallic, metalloceramic or ceramic electrodes with pore sizes of above1 μm.

EXAMPLE 4.2

Ce, Sr and Y carboxylates with concentrations of 0.05-1.5 mole/l areproduced by extraction of water salts of cerium, strontium and yttriumto a mixture of carbonic acids with the general formulaH(CH₂—CH₂)_(n)CR′R″—COOH, where R′ is CH₃, R″ is C_(m)H_((m+1)) and m isfrom 2 to 6, with an average molecular weight of 140-250. The excessquantity of carbonic acids act as solvent. Ce, Sr and Y carboxylates aremixed in proportions corresponding to the stoichiometric composition ofthe [(Y_(0.5)Sr_(0.5))_(0.4)Ce_(0.6)]O_(x) electrolyte.

The carboxylate solution is mixed with 3-100 nm sized nanometricparticles with the [(Y_(0.5)Sr_(0.5))_(0.4)Ce_(0.6)]O_(x) composition.

The volume ratio of the nanometric particles is 5-50% of the organicliquid volume.

Organogel according to Example 4.2 is used preferably for the productionof the dense outer [(Y_(0.5)Sr_(0.5))_(0.4)Ce_(0.6)]O_(x) compositionelectrolyte layer on the surface of the inner[(Y_(0.5)Sr_(0.5))_(0.4)Ce_(0.6)]O_(x) layer or on the surface of anyother sublayer.

EXAMPLE 5

Organogel for the production of electrolyte of the Ce—Bi—Ox systemcomposition, e.g. Ce_(0.6)Bi_(0.4)O₂.

EXAMPLE 5.1

Ce and Bi carboxylates with concentrations of 0.05-1.5 mole/l areproduced by extraction of water salts of cerium and bismuth to a mixtureof carbonic acids with the general formula H(CH₂—CH₂)_(n)CR′R″—COOH,where R′ is CH₃, R″ is C_(m)H_((m+1)) and m is from 2 to 6, with anaverage molecular weight of 140-250. The excess quantity of carbonicacids act as solvent. Ce and Bi carboxylates are mixed in proportionscorresponding to the stoichiometric composition of theCe_(0.6)Bi_(0.4)O₂ electrolyte.

The solution is mixed with 3-100 nm sized nanometric particles with theCe_(0.6)Bi_(0.4)O₂ composition.

The volume ratio of the nanometric particles is 50-85% of the organicliquid volume.

Organogel according to Example 5.1 is used preferably for the productionof the inner nanoporous three-dimensional Ce_(0.6)Bi_(0.4)O₂ compositionelectrolyte layer on metallic, metalloceramic or ceramic electrodes withpore sizes of above 1 μm.

EXAMPLE 5.2

Ce and Bi carboxylates with concentrations of 0.05-1.5 mole/l areproduced by extraction of water salts of cerium and bismuth to a mixtureof carbonic acids with the general formula H(CH₂—CH₂)_(n)CR′R″—COOH,where R′ is CH₃, R″ is C_(m)H_((m+1)) and m is from 2 to 6, with anaverage molecular weight of 140-250. The excess quantity of carbonicacids act as solvent. Ce and Bi carboxylates are mixed in proportionscorresponding to the stoichiometric composition of theCe_(0.6)Bi_(0.4)O₂ electrolyte.

The solution is mixed with 3-100 nm sized nanometric particles with theCe_(0.6)Bi_(0.4)O₂ composition.

The volume ratio of the nanometric particles is 5-50% of the organicliquid volume.

Organogel according to Example 5.2 is used preferably for the productionof the dense outer Ce_(0.6)Bi_(0.4)O₂ composition electrolyte layer onthe surface of the inner Ce_(0.6)Bi_(0.4)O₂ layer or on the surface ofany other sublayer.

EXAMPLE 6

Method of fabricating an electrode-electrolyte pair comprising amicroporous electrode and a two-layered electrolyte based on ceriumdioxide.

The electrode materials for this example can be as follows:

ceramic cathode, e.g. of the perovskites group of the manganites,cobaltites, nickelites, chromites etc. family;

metallic cathode made from, e.g. ferritic steel;

metalloceramic anode, e.g. of the Ni—CeO₂, Co—CeO₂, Cu—CeO₂ etc. system;

metallic anode made from foam metal or volume mesh consisting of nickel,cobalt or their alloys.

The electrode shape is flat or pipe-like. The electrode may havewell-developed surface roughness, porosity of 30 to 70% and pore size of1 to 30 μm.

EXAMPLE 6.1

Method of fabricating a pair of a La_(1-x)Sr_(x)Co O₃ cathode and atwo-layered (CeO₂)0.8(SmO_(1.5))_(0.2) (SDC) based electrolyte.

The cathode has a porosity of 30% and an average pore size of 5 μm.

The electrolyte is produced by thermal destruction. The deposition isperformed in at least two stages.

At the first stage, the inner nanoporous three-dimensional SDCelectrolyte layer is produced, primarily in the electrode surface pores.The function of the inner SDC electrolyte layer is as follows:

-   1. transformation of large cathode surface pores to a nanoporous    material corresponding to the SDC electrolyte composition;-   2. relieving of the internal and thermal stresses at the phase    boundary of the two contacting materials and in the electrode    material layer towards the electrolyte;-   3. elimination of the negative effect of surface stress    concentrators in the electrode material;-   4. maximizing the electrochemical contact area with the electrolyte    at the electrolyte side.

The inner SDC electrolyte layer is obtained using the organogelaccording to Examples 1.1 or 1.3.

The organogel is deposited onto the cold surface with a roller bypressing it into the electrode surface pores or by one-side vacuumimpregnation of the porous electrode. Destruction is performed byheating the electrode to 500-800° C. in an argon atmosphere or in anargon and hydrogen mixture at reference pressure. Destruction produces,on the heated electrode surface, a partially amorphous three-dimensionallayer of nanoporous SDC electrolyte penetrating into the electrode poresto 10-15 μm. Electrolyte properties are stabilized by crystallizationannealing at 600-1100° C. exceeding the working temperature of theelectrochemical device by at least 15%, the electrolyte grain size being20-1000 nm.

At the second stage, a dense two-dimensional SDC electrolyte layer isproduced on the surface of the preliminarily synthesized SDC electrolytesublayer.

This is performed using the organogel according to Examples 1.2 or 1.4.The organogel is deposited onto the cold functional sublayer surfacewith subsequent heating to 500-800° C. in an argon atmosphere or in anargon and hydrogen mixture or onto the sublayer surface heated to500-800° C. in a similar atmosphere. The final treatment is in air at600-1100° C. exceeding the working temperature of the electrochemicaldevice by at least 15%. As a result, a dense, defect- and crack-freetwo-dimensional 8YSZ electrolyte layer with a grain size of 20-1000 nmforms on the sublayer surface. The thickness of this latter layer is3-10 μm.

Organogel according to Example 1.4 can be deposited onto the sublayersurface heated to 200-500° C. in air or in an inert atmosphere.Destruction produces dense, defect- and crack-free two-dimensional SDCelectrolyte layer on the sublayer surface. The final treatment is in airat 800-1100° C. exceeding the working temperature of the electrochemicaldevice by at least 15%. As a result, a dense, defect- and crack-freetwo-dimensional SDC electrolyte layer with a grain size of 20-1000 nmforms on the sublayer surface. The thickness of this latter layer is 1-5μm.

The electrolyte produced as above was a continuous layer part of which,i.e. the three-dimensional nanoporous electrolyte, penetrated into theporous electrode structure, and the other part, i.e. the densetwo-dimensional layer was uniformly distributed over the surface andinherited its roughness pattern.

EXAMPLE 6.2

Method of fabricating a pair of a La_(1-x)Sr_(x)Co O₃ cathode and atwo-layered electrolyte based on cerium dioxide of differentcompositions.

The cathode has a porosity of 30% and an average pore size of 5 μm.

The electrolyte is produced by thermal destruction. The deposition isperformed in at least two stages.

At the first stage, the inner nanoporous three-dimensional(CeO₂)_(0.8)(GdO_(1.5))_(0.2) (GDC) electrolyte layer having a combinedionic and electronic p-type of conductivity is produced. The function ofthe inner (CeO₂)_(0.8)(GdO_(1.5))_(0.2) electrolyte layer is as follows:

-   1. transformation of large cathode surface pores to a nanoporous    material corresponding to the (CeO₂)_(0.8)(GdO_(1.5))_(0.2)    electrolyte composition;-   2. relieving of the internal and thermal stresses at the phase    boundary of the two contacting materials and in the electrode    material layer towards the electrolyte;-   3. elimination of the negative effect of surface stress    concentrators in the electrode material;-   4. maximizing the electrochemical contact area with the electrolyte    at the electrode side;-   5. maximizing the electrochemical contact area with the electrolyte    at the electrolyte side;-   6. minimization of the cathode resistance.

The inner (CeO₂)_(0.8)(GdO_(1.5))_(0.2) electrolyte layer is producedusing the organogel according to Example 2.1.

The inner layer production method is as in Example 6.1.

At the second stage, a dense two-dimensional CeO₂—Sm₂O₃ (SDC) orCeO₂—Y₂O₃ (YDC) electrolyte layer is produced on the surface of thepreliminarily synthesized (CeO₂)_(0.8)(GdO_(1.5))_(0.2) electrolytesublayer.

This is performed using the organogel according to Examples 1.2 or 1.4for SDC or organogel according to Example 3.2 for YDC. The dense outerlayer production method is as in Example 6.1.

The electrolyte produced as above was a continuous layer part of which,i.e. the three-dimensional nanoporous electrolyte of the GDCcomposition, penetrated into the porous electrode structure, and thesurface layer, i.e. the dense two-dimensional SDC or YDC layer wasuniformly distributed over the surface and inherited its roughnesspattern.

EXAMPLE 6.3

Method of fabricating a pair of a 50% CoO-50% GDC anode and atwo-layered electrolyte based on cerium dioxide of differentcompositions.

The cathode has a porosity of 30% and an average pore size of 3 μm.

The electrolyte is produced by thermal destruction. The deposition isperformed in at least two stages.

At the first stage, the inner nanoporous three-dimensional GDCelectrolyte layer having a combined ionic and electronic p-type ofconductivity is produced. The function of the inner GDC electrolytelayer is as follows:

-   1. transformation of large cathode surface pores to a nanoporous    material corresponding to the GDC electrolyte composition;-   2. relieving of the internal and thermal stresses at the phase    boundary of the two contacting materials and in the anode material    layer towards the electrolyte;-   3. elimination of the negative effect of surface stress    concentrators in the anode material;-   4. maximizing the electrochemical contact area with the electrolyte    at the anode side;-   5. maximizing the electrochemical contact area between the gaseous    fuel, the anode material and the electrolyte;-   6. minimization of the anode resistance.

The inner GDC electrolyte layer is produced using the organogelaccording to Example 2.1.

The inner layer production method is as in Example 6.1.

At the second stage, a dense two-dimensional SDC electrolyte layer isproduced on the surface of the preliminarily synthesized GDC electrolytesublayer.

This is performed using the organogel according to Example 1.4. Thedense outer layer production method is as in Example 6.1.

The electrolyte produced as above was a continuous layer part of which,i.e. the three-dimensional nanoporous electrolyte of the GDC compositionwith a combined type of conductivity, penetrated into the porouselectrode structure to 6-8 μm, and the surface layer, i.e. the densetwo-dimensional SDC layer was uniformly distributed over the surface andinherited its roughness pattern.

EXAMPLE 6.4

Method of fabricating a pair of a (steel, nickel, cobalt or their alloy)anode and a two-layered electrolyte based on cerium dioxide.

The metallic anode is a foam metal or a volume mesh and has a porosityof 30-60% and an average pore size of 10-50 μm.

The electrolyte is produced by thermal destruction. The deposition isperformed in at least two stages.

At the first stage, the inner nanoporous three-dimensional[(Y_(0.5)Sr_(0.5))_(0.4)Ce_(0.6)]O_(x) electrolyte layer having a highstability against reduction in a gaseous fuel atmosphere, is produced.This is performed using the organogel according to Example 1.4. Theinner electrolyte layer production method and functions are as inExample 6.1.

At the second stage, a dense two-dimensional[(Y_(0.5)Sr_(0.5))_(0.4)Ce_(0.6)]O_(x) electrolyte layer is produced onthe surface of the preliminarily synthesized sublayer.

This is performed using the organogel according to Example 4.2. Thedense outer layer production method is as in Example 6.1.

The electrolyte produced as above was a continuous layer part of which,i.e. the three-dimensional nanoporous electrolyte of the[(Y_(0.5)Sr_(0.5))_(0.4)Ce_(0.6)]O_(x) composition, penetrated into theporous electrode structure to 20-100 μm, and the surface layer, i.e. thedense two-dimensional [(Y_(0.5)Sr_(0.5))_(0.4)Ce_(0.6)]O_(x) layer wasuniformly distributed over the surface and inherited its roughnesspattern.

EXAMPLE 6.45

Method of fabricating a pair of a (steel, nickel, cobalt or their alloy)cathode and a two-layered electrolyte based on cerium dioxide.

The metallic anode is a foam metal or a volume mesh and has a porosityof 30-60% and an average pore size of 10-50 μm.

The electrolyte is produced by thermal destruction. The deposition isperformed in at least two stages.

At the first stage, the inner nanoporous three-dimensionalCe_(0.6)Bi_(0.4)O₂ electrolyte layer having a high stability againstreduction in a gaseous fuel atmosphere, is produced. This is performedusing the organogel according to Example 5.1. The inner electrolytelayer production method and functions are as in Example 6.1.

At the second stage, a dense two-dimensional electrolyte layer based oncerium dioxide is produced as in Examples 6.1-6.4.

The second embodiment of the electrode-electrolyte pair suggested anddisclosed herein (FIG. 2) is fabricated using the second suggestedfabrication method.

The electrolyte production method is based on destruction(decomposition) of the organic component of the organic solution ofcerium and stabilizing metal salts deposited onto the electrode surface.The organic salts are carboxylates of cerium, yttrium, alkaline,alkaline-earth and rare-earth metals in a mixture of α-branchingcarbonic acids with the general formula H(CH₂—CH₂)_(n)CR′R″—COOH, whereR′ is CH₃, R″ is C_(m)H_((m+1)) and m is from 2 to 6, with an averagemolecular weight of 140-250. The organic salt solvent is any carbonicacids, e.g. toluene, octanol or other organic solvent.

As a result of the destruction, an amorphous oxide layer forms on thesurface, the composition of which corresponds to that of stabilizedcerium oxide. Unlike other solution deposition methods that producemetal oxide powders on the surface that need high-temperature sintering,the method disclosed herein allows direct production of a dense anddefect-free electrolyte layer at low temperatures, this being afundamental distinctive feature of the method.

The first stage is deposition of the solution onto the surface of theporous electrode using any known method, preferably, spraying orprinting. Due to the high liquidity and wetting capacity of thesolution, impregnation of the surface pores sized less than 1 μm to adepth of 1-5 μm occur automatically and does not requires any specialmethods.

The second stage is destruction (decomposition) to produce a denseelectrolyte layer on the surface and remove the organic components in agaseous state.

The two above process stages can be unified by depositing the solutiononto the heated electrode surface, provided the surface temperature issufficient for destruction.

The electrolyte layer can be synthesized using any process that causesdestruction of the organic part of the solution, e.g. thermal, inductionor infrared heating, or electron or laser beam impact or plasmachemicalimpact.

The simplest and cheapest method from the technological and economicalviewpoints is thermal destruction (pyrolysis). The destructiontemperature is within 800° C., the preferable thermal destructiontemperature range being 200-600° C. The process can be conducted underatmospheric pressure in air or in an inert or weakly reducing gasatmosphere. The temperature and the gas atmosphere determine thedestruction rate and hence electrolyte properties. Stabilization of theintermediate amorphous state is preferably performed in an inert orweakly reducing gas atmosphere or using high-rate destruction methods.The minimum electrolyte layer formation time is 30 seconds. Destructionin air increases the oxide layer formation rate, the minimum electrolytelayer formation time in this case being 5-10 seconds.

The method of solution deposition onto the heated surface withsimultaneous destruction is more rapid and efficient, but it leads toelevated stresses in the electrolyte layer and at the phase boundary.

The method of solution deposition onto the cold surface with subsequentdestruction is less efficient, but it reduces the stress level in thelayer and produces a layer that is more uniform across its thicknesswhich is important, e.g. for the fabrication of an electrode-electrolytepair having a high surface area. Moreover, this method is preferable formultiple electrolyte layer deposition to exclude electrolyte layerrejects as multiple layer deposition heals possible defects.

The final synthesis of crystalline electrolyte from the already formedamorphous material layer implies final air heat treatment. Preferably,the heat treatment temperature should not exceed the working temperatureof the electrochemical device by more than 10-15%.

The distinctive feature of this method is the possibility of producingthin defect-free cerium dioxide electrolyte layers composing anelectrode-electrolyte layer with two-layered electrolyte, e.g.,ZrO₂/CeO₂, BiO₂/CeO₂ or La(Sr)Ga(Mg)O₃/CeO₂. This reduces the workingtemperature of the fuel cells and increases their efficiency, this beingan urgent problem today.

The choice of the solution deposition and destruction method and gasatmosphere composition provide for the high adaptability of the methodand allow producing high-quality electrode-electrolyte pairs with dueregard to the properties and parameters of the composing materials.

Below, the possibilities of the second electrode-electrolyte pairfabrication method will be illustrated with specific examples that donot limit the scope of this invention.

EXAMPLE 7

Method of fabricating an electrode-electrolyte pair comprising ananoporous electrode (sublayer) and a dense thin electrolyte based oncerium dioxide.

The electrode or electrode sublayer materials for this example can be asfollows:

ceramic cathode, e.g. of the perovskites group of the manganites,cobaltites, nickelites, chromites etc. family;

metallic cathode made from, e.g. ferritic steel with a functionalcathodic sublayer;

metalloceramic anode, e.g. of the Ni-GDC, Co-GDC etc. system;

metallic anode made from foam metal or volume mesh consisting of nickel,cobalt or their alloys with an anode sublayer;

electrode with other electrolyte on the surface.

The electrode shape is flat or pipe-like. The electrode (sublayer) mayhave well-developed surface roughness, porosity of 0 to 60% and a poresize of less than 1 μm.

EXAMPLE 7.1

Method of fabricating a pair of a 50% NiO-50% 3YSZ anode with a 50%NiO-50% GDC sublayer and a dense SDC electrolyte layer.

The cathode has a porosity of 35% and an average pore size of less than1 μm. The sublayer thickness is 10 μm.

The electrolyte is produced by thermal destruction. The deposition isperformed in at least one stage.

The dense SDC electrolyte layer is produced using a solution of amixture of cerium and samarium carboxylates in toluene with a totalcerium and samarium concentration of 0.5 mole/l, their molar ratiocorresponding to the SDC electrolyte stoichiometric composition.

The solution is deposited onto the cold surface by printing, followingwhich the anode is air heated at atmospheric pressure to 300° C. Underthese conditions, the anode sublayer surface pores are impregnated to adepth of 3-5 μm. Destruction of the organic part of the solutionproduces a dense amorphous surface SDC layer penetrating into thesublayer to 3-5 μm, the layer thickness on the surface being less than 1μm. If the SDC layer thickness should be increased, the deposition anddestruction cycle is repeated.

The final annealing at 600 and 1000° C. produces cubic fluoride ceriumdioxide with a density of 99.8% of the theoretical one and a grain sizeof 30-40 and 800-1000 nm, respectively.

EXAMPLE 7.2

Method of fabricating a pair of a metallic anode with a nanoporousscandium stabilized 50% CoO-50% GDC sublayer and a dense SDC electrolytelayer.

The cathode has a porosity of 30% and an average pore size of less than1 μm. The sublayer thickness is 25 μm.

The electrolyte is produced by solution deposition with simultaneousthermal destruction.

The dense SDC electrolyte sublayer is produced using a solution of amixture of cerium and samarium carboxylates as in Example 7.1, the totalcerium and samarium concentration being 0.05-0.5 mole/l, and their ratiobeing stoichiometric.

The solution is deposited onto the surface heated to 400° C. by multipleprinting at atmospheric pressure in an argon atmosphere. Under theseconditions (during the first deposition cycle), the anode sublayersurface pores are impregnated to a depth of 1-2 μm with further increaseof the SDC electrolyte layer. Each cycle is 1 minute long.

This technology produces a dense amorphous surface SDC layer penetratinginto the sublayer to 1-2 μm, the layer thickness on the surface being0.5 to 5 μm.

The final annealing at 800° C. produces cubic cerium dioxide with adensity of 99.5% of the theoretical one and a grain size of 20-50 nm.

EXAMPLE 7.3

Method of fabricating a pair of a La_(0.6)Sr_(0.4)CoO₃ cathode with aLa_(0.6)Sr_(0.4)CoO₃ sublayer and a dense bismuth stabilized ceriumdioxide (BSC) electrolyte layer.

The cathode has a porosity of 35% and an average pore size of less than1 μm. The sublayer thickness is 5 μm.

The electrolyte is produced by thermal destruction. The deposition isperformed in at least one stage.

The dense BSC electrolyte layer is produced using a solution of amixture of cerium and bismuth carboxylates in toluene with a totalcerium and bismuth concentration of 0.7 and 1.2 mole/l, respectively,their molar ratio corresponding to the BSC electrolyte stoichiometriccomposition.

The solution is deposited onto the cold surface by spraying, followingwhich the cathode is air heated at atmospheric pressure to 300° C. Underthese conditions, the cathode sublayer surface pores are impregnated toa depth of up to 5 μm. Destruction of the organic part of the solutionproduces a dense amorphous surface BSC layer penetrating into thesublayer to the full sublayer depth, the layer thickness on the surfacebeing 0.3 μm. If the BSC layer thickness should be increased, thedeposition and destruction cycle is repeated.

The final annealing at 600° C. produces tetragonal zirconium dioxidewith a density of 99.99% of the theoretical one and a grain size of10-30 mn.

EXAMPLE 7.4

Method of fabricating a pair of an anode the surface of which containselectrolyte of stabilized zirconium dioxide and dense SDC electrolyte.

The anode was kermet 50%NiO-50% 8; YSZ. The 8YSZ electrolyte layer had adensity of 2 μm and a porosity of 10%.

The dense SDC electrolyte layer is produced using a solution of amixture of cerium and samarium carboxylates in toluene with a totalzirconium and samarium concentration of 0.05 mole/l, their molar ratiocorresponding to the (CeO₂)_(0.8)(SmO_(1.5))_(0.2) stoichiometriccomposition.

The solution is deposited onto the surface heated to 400° C. by multipleprinting at atmospheric pressure in an argon atmosphere. Under theseconditions, the pores and 8YSZ defects are covered, and a dense(CeO₂)_(0.8)(SmO_(1.5))_(0.2) electrolyte layer forms. After 20deposition cycles the outer (CeO₂)_(0.8)(SmO_(1.5))_(0.2) electrolytelayer reached 3 μm.

1. Electrode-electrolyte pair comprising a microporous electrode to thesurface of which is deposited a multilayered solid electrolyte based oncerium dioxide with stabilizing additions, the solid electrolyteconsisting of the inner nanoporous three-dimensional solid electrolytelayer with a grain size of within 1000 nm which fills, at leastpartially, the surface pores of the microporous electrode to a depth of5-50 μm, and a dense outer electrode layer with a grain size of within1000 nm located on the surface of said inner layer. 2.Electrode-electrolyte pair according to claim 1, wherein said inner andouter electrolyte layers have similar or different compositions. 3.Electrode-electrolyte pair according to claim 1, wherein said innerelectrolyte layer has a combined amorphous and nanocrystallinestructure.
 4. Electrode-electrolyte pair according to claim 1, whereinsaid outer electrolyte layer has an amorphous structure. 5.Electrode-electrolyte pair according to claim 1, wherein saidstabilizing additions are yttrium and/or alkaline-earth and/or rareearth metals and/or bismuth.
 6. Electrode-electrolyte pair according toclaim 1, wherein said electrode is made of a microporous ceramic ormetallic or metalloceramic material with pore sizes of above 1 μm. 7.Electrode-electrolyte pair according to claim 1, wherein said electrodeis a cathode or anode of flat or pipe-like shape. 8.Electrode-electrolyte pair according to claim 7, wherein said anode ismade of a volume mesh or a foam material.
 9. Electrode-electrolyte pairfabrication method comprising the formation, on the microporouselectrode surface, of a partially electrode-penetrating multilayeredsolid electrolyte based on cerium dioxide with stabilizing additions, towhich end the microporous electrode surface is initially impregnatedwith organogel consisting of particles of cerium dioxide withstabilizing additions and an organic solution containing organic saltsof cerium and the stabilizing metals, and destruction of the organogelorganic part that leads to the chemical deposition of the innernanoporous three-dimensional solid electrolyte layer on the electrodesurface, following which the inner organogel layer is deposited onto thesurface, said layer consisting of nanosized particles of cerium dioxidewith stabilizing additions and an organic solution containing organicsalts of cerium and the stabilizing metals, and destruction of theorganogel organic part that leads to the chemical deposition of thedense outer layer of the multilayered electrolyte onto the inner layersurface.
 10. Method according to claim 9, wherein said inner and outerelectrolyte layers are produced using organogel of similar or differentcompositions.
 11. Method according to claim 10, wherein said stabilizingadditions are yttrium and/or alkaline-earth and/or rare earth metalsand/or bismuth.
 12. Method according to claim 10, wherein theimpregnation of said porous electrode surface with organogel isperformed in vacuum of by mechanical pressing the organogel into theporous electrode surface.
 13. Method according to claim 10, wherein saiddestruction is performed by high-energy impact that causes thedecomposition of the organic part of the organogel, e.g. thermal,induction or infrared heating, or electron or laser beam impact orplasmachemical impact.
 14. Method according to claim 13, wherein saidorganogel destruction is performed with high-rate pyrolysis attemperatures within 800° C. in an oxidizing, inert or weakly reducinggas atmosphere.
 15. Method according to claim 9, wherein organogelorganic part destruction is performed simultaneously or sequentiallywith the impregnation or organogel deposition onto the inner layersurface.
 16. Method according to claim 15, wherein during organogelimpregnation of the electrode or organogel deposition to the inner layersurface with simultaneous destruction, the organogel is deposited to thesurface to be coated by spraying or printing.
 17. Method according toclaim 15, wherein during organogel impregnation of the electrode ororganogel deposition to the inner layer surface with subsequentdestruction, the organogel is deposited to the cold surface of theelectrode or the inner layer with subsequent high-rate heating of theelectrode.
 18. Method according to claim 9, wherein organogelimpregnation of the electrode or organogel deposition to the inner layersurface and organogel destruction are performed in one or multiplestages.
 19. Organogel used for the fabrication of theelectrode-electrolyte pair contains nanosized particles of ceriumdioxide with stabilizing additions and an organic solution containingorganic salts of cerium and the stabilizing metals, a mixture ofα-branching carbonic acids with the general formulaH(CH₂—CH₂)_(n)CR′R″—COOH, where R′ is CH₃, R″ is C_(m)H_((m+1)) and m isfrom 2 to 6, with an average molecular weight of 140-250.
 20. Organogelaccording to claim 19, wherein said stabilizing additions are yttriumand/or alkaline-earth and/or rare earth metals and/or bismuth. 21.Organogel according to claim 19, wherein said organic solvent is amixture of α-branching carbonic acids with the general formulaH(CH₂—CH₂)_(n)CR′R″—COOH, where R′ is CH₃, R″ is C_(m)H_((m+1)) and m isfrom 2 to 6, with an average molecular weight of 140-250, or carbonicacid and/or any organic solvent of carbonic acid metal salts. 22.Organogel according to claim 19, wherein said organogel containsnanosized particles 3 to 100 nm in size.
 23. Organogel according toclaim 19, wherein the concentration of stabilizing additions in ceriumand metal salts in the organogel is selected at 0.05 to 1 mole/l in aratio corresponding to the electrolyte stoichiometric composition. 24.Organogel according to claim 19, wherein the volume ratio of thenanosized particles in the organogel is within 85%. 25.Electrode-electrolyte pair comprising a nanoporous electrode to thesurface of which is deposited a layer or dense three-dimensionedelectrolyte based on cerium dioxide with stabilizing additions the grainsize of which is within 1000 nm, the electrolyte filling the surfacepores of the nanoporous electrode to a depth of 1-5 μm. 26.Electrode-electrolyte pair according to claim 25, wherein saidelectrolyte has an amorphous structure.
 27. Electrode-electrolyte pairaccording to claim 25, wherein said stabilizing additions are yttriumand/or alkaline-earth and/or rare earth metals and/or bismuth. 28.Electrode-electrolyte pair according to claim 25, wherein said electrodeis in a microporous ceramic or metallic or metalloceramic material withpore sizes of within 1 μm.
 29. Electrode-electrolyte pair according toclaim 25, wherein said electrode is an anode or cathode with a flat orpipe-like shape.
 30. Electrode-electrolyte pair fabrication methodcomprising the formation, on the microporous electrode surface, of adense three-dimensional solid electrolyte layer based on cerium dioxidewith stabilizing additions, for which end the nanoporous electrodesurface is initially impregnated with an organic solution containingorganic salts of cerium and the stabilizing metals, a mixture ofα-branching carbonic acids with the general formulaH(CH₂—CH₂)_(n)CR′R″—COOH, where R′ is CH₃, R″ is C_(m)H_((m+1)) and m isfrom 2 to 6, with an average molecular weight of 140-250, anddestruction of the organogel organic part that leads to the chemicaldeposition of the solid electrolyte on the electrode surface.
 31. Methodaccording to claim 30, wherein said stabilizing additions are yttriumand/or alkaline-earth and/or rare earth metals and/or bismuth. 32.Method according to claim 30, wherein said organic solvent is carbonicacid or toluene or octanol or any organic solvent of carbonic acid metalsalts.
 33. Method according to claim 30, wherein said destruction isperformed by high-energy impact that causes the decomposition of theorganic part of the organogel, e.g. thermal, induction or infraredheating, or electron or laser beam impact or plasmachemical impact. 34.Method according to claim 33, wherein said organogel destruction isperformed with high-rate pyrolysis at temperatures within 800° C. in anoxidizing, inert or weakly reducing gas atmosphere.
 35. Method accordingto claim 30, wherein said organogel organic part destruction isperformed simultaneously or sequentially with impregnation.
 36. Methodaccording to claim 35, wherein during electrode impregnation withsimultaneous destruction, the solution is deposited to the surface to becoated by spraying or printing.
 37. Method according to claim 35,wherein during electrode impregnation with subsequent destruction, thesolution is deposited to the cold surface of the electrode withsubsequent high-rate heating of the electrode.
 38. Method according toclaim 30, wherein the concentration of stabilizing additions is selectedat 0.05 to 1 mole/l in a ratio corresponding to the electrolytestoichiometric composition.
 39. Organogel according to claim 30, whereinsaid solution is deposited onto the electrode surface and destruction inone or multiple stages.